True field of view calculator

Enter the apparent field of the eyepiece and the focal lengths of the telescope and the eyepiece to get the true field of view, in degrees and in arcminutes.

Enter your values, then calculate.

Method and limitations

True field of view = apparent field of view ÷ magnification, where magnification = telescope focal length ÷ eyepiece focal length (both in millimetres). The apparent field is in degrees, greater than 0 and at most 180. The result is in degrees, shown to two decimal places, and in arcminutes (the result in degrees × 60), shown to the nearest whole number.